1. Field of the Invention
The present invention relates to voice messaging and interactive voice response (IVR) systems and, more particularly, to the interaction with voice messaging and IVR systems in an Internet-like environment.
2. Description of the Related Art
Voice mail and Interactive Voice Response (IVR) systems have become a nearly ubiquitous feature of telephony usage in the U.S. Access to public data networks such as the Internet has also increased greatly in recent years.
Currently, there is a product available which allows two Internet-connected multimedia computers to establish and conduct a telephone call over a packet data network such as the Internet. This particular product has limited usefulness because it requires the computers to possess certain high-end capabilities and thus is not appropriate for many computer users.
Further, one characteristic of current Internet telephony, whether computer-to-computer or computer-to-POTS (plain old telephone service) telephone is that it can be of low quality, particularly with respect to the transmission delays encountered by the voice signals. This delay, called xe2x80x9clatency,xe2x80x9d is predominantly due to the transmission characteristics of packet data networks such as the Internet. It is also important to note that the transport protocol used to transmit voice in Internet telephony products today is UDP, an unreliable, non-session oriented protocol. To summarize, the methods traditionally employed for digital data transmission over packet data networks such as the Internet are not the best-suited methods for transmitting real-time voice over the Internet. Conversely, the best methods for real-time voice transmission are not well-suited to digital data transmission and are also more complicated than digital data transfer methods.
FIG. 1 depicts a conventional real-time voice transmission system for connecting a computer via a packet data network, such as the Internet, with traditional public switched telephone network (PSTN) services using a traditional Internet Telephony Gateway Platform (ITGP). A POTS (plain old telephone service) telephone 100 is connected via a PSTN 110 to a voice mail (VM) system 120 and an Interactive Voice Response (IVR) system 130. A multimedia computer 160 is connected to the Internet 150, which is in turn connected to the ITGP 140, which ITGP is linked to the PSTN 110. A system such as that shown in FIG. 1 would not be ideal for a user wishing to perform voice mail retrieval or IVR functions using a computer via a packet data network because the real-time voice protocol is not optimized for digital signal transmission (necessary for IVR and voice mail retrieval) and is also needlessly complicated for functions which do not require real-time voice transmission.
A further disadvantage of traditional ITGPs is that a technical compromise must be struck with respect to the size of the receiver buffer queue. Since there can be large amounts of jitter (the variance in delay of sound packet arrival times) in a general packet network, it is desirable to make a large receiver buffer queue which holds many of the incoming sound packets before they are played out through the speakers to the user. However, to limit the amount of delay in the conversation, it is desirable to keep the receiver buffer small. This leads to a tradeoff which can compromise system performance.
Traditional ITGPs use voice coders/decoders (codecs) to digitize and compress the speech being carried across the packet network. Frequently, to attain maximum compression, these codecs make assumptions about the sound signal upon which they operate, namely that the sound signal is a voice rather than any other arbitrary signal (e.g., music). Consequently, using a traditional ITGP, if a user depresses a button on the keypad of a touchtone telephone to generate a DTMF tone, the compression of the non-voice audio signal is generally not as accurate as it would be if handled by a system optimized for digital tones. Due to the degraded nature of the transmission of DTMF tones, if the receiving end of the telephone connection is an IVR or voice mail system, the apparatus for detecting DTMF tones may fail to operate properly. Moreover, since traditional ITGPs and Internet Telephony users make no distinction between voice and DTMF tones, the DTMF tones are encoded as if they were voice and therefore use the same bandwidth on the network connection as if voice were being transmitted.
Traditional ITGPs may not allow DTMF tones to be transmitted at all once a conversation starts. If they do, it is usually accomplished by typing in a digit at a keyboard or by clicking on a graphical representation of a telephone keypad on a computer screen. For the purposes of Internet Telephony, the capabilities of the client computer are therefore on par with the capabilities of a traditional telephone.
Another method of computer-based retrieval of voice mail, described by Gordon in U.S. Pat. No. 5,608,786, uses a unified messaging system that collects a user""s messages, either e-mail, voice mail, or fax, in one central location and enables them to be retrieved via remote computer. This method does not allow access to traditional PSTN voice mail, but rather provides a separate collection system for voice and other messages and therefore requires equipment and services above and beyond traditional PSTN voice mail and a user""s personal computer.
In accordance with the present invention, there is provided a method and system for accessing a remote system via a computer connected to a packet data network. A Packet Data Network Gateway (PDNG) is connected to the packet data network. The PDNG receives a signal representing a DTMF tone transmitted from the computer, generates the DTMF tone at corresponding to the received signal, and transmits the generated DTMF tone to the remote system. The PDNG receives a response from the remote system and creates at least one voice packet for transmission to the computer over the packet data network. The remote system may be a voice messaging system or an interactive voice response (IVR) system.
It is not intended that the present invention be summarized here in its entirety. Rather, further features, aspects and advantages of the present invention are set forth in or are apparent from the following description and drawings.